Speaking to Russian state TV, Patriarch Kirill said smartphone users should be careful when using the "worldwide web of gadgets" because it represented "an opportunity to gain global control over mankind".

"The Antichrist is the person who will be at the head of the worldwide web, controlling all of humankind," he said.

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"Every time you use your gadget, whether you like it or not, whether you turn on your location or not, somebody can find out exactly where you are, exactly what your interests are and exactly what you are scared of," Patriarch Kirill told Rossiya 1.

"If not today, then tomorrow methods and technology could appear that will not just provide access to all information but will also allow the use of this information.

"Do you imagine what power will be concentrated in the hands of those who gain knowledge about what is going on in the world?

"Such control from one place forebodes the coming of the Antichrist."

Patriarch Kirill said his Church was not against "technological progress", rather "the development of a system that is aimed at controlling a person's identity". But not all social media users were convinced.

"Smile, the Antichrist is about to fly out," tweeted another, along with an image of a woman taking a selfie with Patriarch Kirill and other church representatives.

Patriarch Kirill is close to Russian president Vladimir Putin, who participates in big Church celebrations and has gone on pilgrimages to Mount Athos and other famous Orthodox sites. Many Russian Orthodox priests closely identify with President Putin's nationalist agenda.